The present invention relates to a pen stem structure with a decoration, including a pen stem and a transparent rod body connected with one end of the pen stem. The rod body defines a close space in which a water soluble solvent and an oily color solvent are contained. The solvents are insoluble in each other, so that when shaking the pen during writing, the oily color solvent is isolated from the water soluble solvent and buoys therein to form various patterns.
Many types of pens are commercially available. These pens are designed with various patterns and curves to achieve a better appearance and facilitate holding and writing. However, the conventional pens still lack novel characteristics for expediting desire of purchase.